Melanie: Let’s take 20A. The def is the first two words of clue, and is a fairly well know term for that.

When you get a possible answer to that, use the operation implied in the theme to reduce that word to a remnant segment; ‘ending in battle’ clues part of that segment and ‘zone being evacuated’ the rest of it. If that works out your answer was right!

Re 21D, I have to agree with previous comments. This is the second time this year that I have been baffled by the DA’s use of ‘oddly’. I guess it’s used loosely to mean ‘alternately’ rather than every odd numbered position, so it could be either 1,3,5 etc, or 2,4,6 etc.

Viv,
you shouldn’t accept loose clueing by any setter. Of all the setters that I have solved both in Oz and UK, none of them use ‘oddly’ for the even letters. I think this was purely an oversight from DA.

The problem with DA is that his admirable creativity is not always matched by his execution.
It’s great that he tries to be different but don’t allow lazy, or inaccurate, clueing to be passed off as ‘just his style’.